Halfway to the so-called "Philly Slam" after winning the USPGA Championship last year and the Masters in April, Phil Mickelson pronounced himself more than happy with an opening round of level par in leg three of his four-major quest, the US Open. Which, given the way he played, came as no surprise.

With, in the words of his caddie, an "awesome display around the greens in the middle of his round," the American celebrated his 36th birthday a day early by - in the language favoured by golf's elite - "turning a 76 into a 70".

"I didn't hit very many greens today," admitted Mickelson. "But they are very tough to find. It is very difficult to stop the ball, especially if you are hitting from the rough. The key for me today was that I was able to miss in the right spots and leave myself some relatively easy chip shots. If you do that you can still make pars."

That Mickelson did, 14 times to be exact, his brace of birdies both courtesy of sizeable putts cancelled out by the same number of bogeys, the two occasions on which even his much-vaunted short game could not retrieve his waywardness. No problem though. On a 7,264-yard Winged Foot course all but covered in long grass, such slips were understandable and hardly reason for concern. Mickelson knew all too well that the other 155 players in the field were suffering similarly in the blustery conditions. "Yes, Phil missed a lot of greens, but what was neat was that he took advantage," said his swing coach, Rick Smith. "Over the last six holes he was close to perfect tee-to-green."

While that assessment may have been a little over the top - Smith's charge missed two greens and one fairway over the last third of his round - Mickelson's total was more than satisfactory. "Even par is a good score," he said. "I happen to think that over par is going to win. I suspect that the course will play harder and faster as the week wears on, making the greens even tougher to hit, to chip to and to putt on."

Should that prove to be the case, an ability to hit fairways from the tee is going to assume more importance. To that end, Mickelson, who famously used two drivers during his Masters victory at Augusta National two months ago, had only one, the fader, in his bag yesterday. But that could change. "I may go to a shorter driver, the 43-inch version. As the fairways get harder and faster, accuracy will become more important than sheer length. So the shorter club will help."

It is a thought process that makes sense in such conditions.

Even the strongest players cannot muscle the ball on to the putting surfaces from the USGA's three-tiered rough that grows longer the farther one ventures from the safety of the fairway. "From the first cut you can advance the ball up by the green," claimed Mickelson. "But it"s hard to hit the green. And from the thick stuff all you can do is chop it out. It's just too thick and too tough."

In an attempt to avoid the above scenario, Mickelson is nothing if not meticulous. Take his thought process on the 321-yard sixth hole, the shortest par four on the course. Every eventuality is covered. "Into the wind I couldn't reach the green," he said. "So I hit my driver to leave a relatively easy chip to the green. If it is downwind, I will still hit my driver, to try and get into the bunker in front of the putting surface. There's only one pin under one condition where I would lay back."

Such attention to detail is one example of the stresses imposed on competitors in what Mickelson calls "the hardest major." Caddies feel it, too. "It probably isnt supposed to be fun, but that was no fun," was Mackay's verdict on what, ominously for all concerned, may prove to be the easiest day of the four it will take to identify the new champion.